Displays the comment author name; that is, the one supplied by the commenter. If no name is provided (and "User must fill out name and email" is not enabled under Discussion Options), WordPress will assign "Anonymous" as comment author.
Use get_comment_author() to retrieve the value.
<?php comment_author( $comment_ID ); ?>
<div>Comment by <?php comment_author(); ?>:</div>
apply_filters() Calls 'comment_author' on comment author before displaying
comment_author() is located in